Study links viral infection to juvenile diabetes

LONDON (Reuters) - Italian scientists have found a significant link between juvenile diabetes and a common virus that usually only causes a mild infection - a discovery that may give clues as to what triggers the disease.

In a small study of 112 children with juvenile diabetes, Antonio Toniolo of the University of Insubria in Varese, Italy, found that more than 80 percent had evidence of enterovirus infection in their blood.

Enteroviruses are viruses that can thrive in the gastrointestinal tract.

They are very common - second only to common cold viruses - and most people who are infected with an enterovirus have no obvious illness. Others have flu-like symptoms, aching muscles or a rash and some severe viruses attack the nervous system.

Toniolo stressed that the results did not show a causal link between enteroviruses and diabetes, but said the discovery was in tune with previous studies which have suggested enterovirus infections may be associated with diabetes.

"Infection by different enteroviruses may be linked to the early stages of diabetes," he said.

Juvenile diabetes, also called Type 1 or insulin-dependent diabetes, is an autoimmune disease in which the body destroys its own ability to make insulin. It affects around 22 million people worldwide, according to the World Health Organisation.

The disease develops in people who are genetically susceptible to it and scientists think exposure to some as yet unknown trigger or triggers may be what sets it off.

Toniolo and colleagues tested the blood of 112 children aged between 2 and 16 years at the time they were diagnosed with Type 1 diabetes to see if it contained enteroviral DNA.

The scientists compared their blood with that of children without diabetes. They found low-level enteroviral infectivity in 83 percent of the diabetes patients, compared with 7 percent of children with no diabetes.

"These data do not provide a causal relationship between enterovirus infections and diabetes," Toniolo said in a statement with the study, which was presented at a conference of the American Society for Microbiology in San Diego, California.

"However, the high prevalence of enteroviral genome sequences in newly diagnosed type-1 diabetes cases indicate that different enterovirus types represent a significant biomarker of early stage juvenile diabetes," Toniolo added.

Sufferers of Type 1 diabetes become unable to properly break down sugar. If the disease is untreated, blood vessels and nerves are destroyed, organs fail and patients die.

Toniolo said if similar results were found in studies of patients in other geographic areas, it would suggest that detecting enteroviruses early may help researchers find other environmental factors that lead to type-1 diabetes. This in turn could lead to new ways of preventing or treating the disease.